The present invention relates to an antenna apparatus for use in a radio communication system.
Wireless communication is well known for communication over large distances and also where the communicating devices require a high degree of mobility. More recently, wireless communication has been employed for communication between personal computers (PCs) forming part of a local area network (LAN). To provide wireless connection to the LAN, the PC has to be equipped with an appropriate network interface card (NIC) and a radio modem which can be integrated into the NIC or connected to the NIC, by means of an appropriate cable. An antenna forms an integral part of the modem. Due to the use of small-size PCs, which have standard slots such as those proposed by the Personal Computer Memory Card Association (PCMCIA), reductions in the size of the NIC and modem, and thus the antenna, are required.
Known antenna apparatus such as the Plated Inverted-F Antenna (PIFA), which comprises a rectangular plate having a feed pin and ground pin connecting it to antenna circuitry and the ground plane respectively, is disadvantageous in that it is too large for use in applications of the above-mentioned nature and a simple reduction in the size of the rectangular plate leads to the significant degradation of performance in terms of operational bandwidth and/or gain. Also, the rectangular plate limits the area in which other RF components can be mounted since there is not enough space to mount the components beneath the rectangular plate.